Rodent Trident Maze

The Rodent Trident Maze was created to examine the interactions between motivational state and memory demand. Episodic memory is organized by spatial, temporal, and personal contexts, and can be modulated by motivational states arising from interoceptive cues. The hippocampus plays a key role in episodic memory by encoding organized associations among the multimodal elements that characterize an experience, and hippocampal neurons respond to organizing features of experience other than spatial context. Different motivational states can elicit distinct hippocampal codes in identical places, which can influence memory processes and help select among adaptive behaviors based on past experience. Using the Rodent Trident Maze, the motivational state examined was hunger and this on memory demand.

The Rodent Trident Maze is composed of acrylic which is available in the colours black, grey, blue, white, and clear. A start arm leads to hexagonal central platform. From the platform, three interchangeable arms radiate outwards at 45° angles. At the end of each is located a goal box.

Rodent location can be tracked using a video tracking software package such as Noldus EthoVision, ANY-Maze, or BehaviorCloud.

Pre-Training

Rats were food and water deprived on alternate days

Training:

Rats were trained to approach one goal box for food reward when hungry, a second goal box for water reward when thirsty, and to avoid a third goal box that was never rewarded. The goal boxes were moved randomly between the 3 possible goal locations after each trial. Rats were trained for 6 trials/day with 10-min inter-trial intervals until they reached and maintained an 80% correct choice criterion level of performance.

The following can be assessed using the Rodent Trident Maze

• The task exploits the innate explorative nature of rodents and subjects them to tasks that require them to alternate between the goal arms to retrieve food rewards.
• Protocols include Forced Alternation task and Spontaneous Alternation tasks
• The Rodent Trident can be easily adapted to investigate the different aspects of spatial learning and for different subjects.
• The Rodent Trident Maze can be used to study of hippocampal functions, age-related cognitive decline and anxiety.
• The Rodent Trident Maze can also be utilized in understanding the effects of drugs and toxins and in understanding the underlying pathology of diseases on spatial learning and memory.

Motivational states activate distinct hippocampal representations to guide goal-directed behaviors

Kennedy and Shapiro (2009) explore the role of the hippocampus in guiding goal-directed behaviors during different motivational states. The authors use a rodent model and demonstrate that different motivational states, such as hunger or thirst, activate distinct hippocampal representations that help guide goal-directed behavior towards the appropriate outcome.

The experimental procedure involved six male Long Evans rats, maintained at 85% of their free-feeding body weight. The rats were trained in the Trident maze to approach one goal box for food reward, a second goal box for water reward, and to avoid a third goal box that was never rewarded. After the rats maintained the 80% correct choice performance for six consecutive days, they were implanted with recording electrodes, mounted on the skull over the left dorsal hippocampus.  The recording sessions for the contextual memory retrieval task lasted approximately 50 min and included 25-35 trials.

As the rats performed the contextual memory retrieval task using the Trident maze, the results showed that hippocampal unit activity strongly distinguished the motivation-based memory retrieval conditions. The study also found that hippocampal neurons encoded multiple relationships among the salient features of the task, and that most task-sensitive fields clearly distinguished the conditions in each of the maze regions.

The findings suggest that the hippocampus plays a critical role in integrating motivational states with environmental cues to guide adaptive behavior. This research provides valuable insights into the neural mechanisms underlying motivated behavior and may have implications for understanding and treating psychiatric disorders.

• The Rodent Trident Maze is used to explore goal-directed behaviours during different motivational states.
• This maze can also be used to study other aspects of spatial learning with a range of different subjects.
• Other protocols include forced Alternation tasks and Spontaneous Alternation tasks.
• It is composed of acrylic and is available in a wide variety of colors.
• A start arm leads to a hexagonal platform with 3 interchangeable arms radiating outwards, each interchangeable arm has a goal box at the end.
• Protocols include Forced Alternation task and Spontaneous Alternation tasks
• The Rodent Trident can be easily adapted to investigate the different aspects of spatial learning and for different subjects.
• The Rodent Trident Maze can be used to study hippocampal functions, age-related cognitive decline and anxiety and the understanding of the effects of drugs and toxins and in understanding the underlying pathology of diseases on spatial learning and memory.

Kennedy, P. J., & Shapiro, M. L. (2009). Motivational states activate distinct hippocampal representations to guide goal-directed behaviors. Proceedings of the National Academy of Sciences, 106(26), 10805–10810. doi:10.1073/pnas.0903259106